By way of the so-called national and international roaming, customers of modern mobile radio networks, such as GSM and UMTS, are able to use, in other countries and with other network operators, services of the respective “foreign” mobile radio network. However, in the case of the roaming, the performance features a customer can use in the foreign network are limited to the performance features that have been activated in the home network. This is caused by the fact that during the roaming, the performance features that are activated for the mobile radio customer are queried from the so-called home location register of the home network and the performance features in the foreign network are made available to the customer based on these authorizations.
As a result it is not possible to use additional performance features in the foreign network that are not available in the home network, and which are therefore also not activated for the customer.
An additional shortcoming of the roaming is that a mobile radio customer is reachable in the foreign network only at his international mobile number of the home network. As a result, a caller in the country of the foreign network needs to always use the international home-location number of the mobile radio customer, even though the mobile radio customer is staying in the same country. Additionally, the caller is billed fees for international calls, even though the mobile radio customer is located in the same country.